Introduction:

Screws offer another example of a force distance tradeoff. The Screw has a similar shape to a wheel/axle, but the rotation of the "wheel" part moves the "axle" part in a forward direction. A relatively gentle twisting force can produce a very strong forward force.

Activity:

Try the screws provided by your teacher. Explain the force-distance trade-off involved.

The Essence of The Screw:

• Two cylinders are joined together, with a common axis, so they both spin at the same rate. There are threads around the long cylinder, so it can move forward as it rotates
  • Twisting the head of the screw by one complete rotation moves the screw forward by one complete thread.
• MA = (Length of the spiral thread) / (Length of the screw)

Video of 2007 RGD

Conclusion:

Start to look for materials that could be used as simple machines! Start to collect junk for your RGD!